/*! \file Peridigm_ScratchMatrix.hpp */

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#ifndef PERIDIGM_SCRATCHMATRIX_HPP
#define PERIDIGM_SCRATCHMATRIX_HPP

namespace PeridigmNS {

  //! Utility class for managing dense matrix scratch space; designed for compatibility with Epetra_CrsMatrix.
  class ScratchMatrix{

  public:

    //! Standard constructor.
    ScratchMatrix() : dim(0), data(0) {}

    //! Destructor.
    ~ScratchMatrix(){
      if(dim != 0){
        for(int i=0 ; i<dim ; ++i)
          delete[] data[i];
        delete[] data;
      }
    }

    //! Resizes the scratch space; underlying data arrays are destroyed and reallocated.
    void Resize(int dimension){
      if(dim != 0){
        for(int i=0 ; i<dim ; ++i)
          delete[] data[i];
        delete[] data;
      }
      dim = dimension;
      data = new double*[dim];
      for(int i=0 ; i<dim ; ++i)
        data[i] = new double[dim];
    }
      
    //! Returns the dimension of the matrix.
    int Dimension(){ return dim; }

    //! Access to underlying data array.
    const double *const * Data(){ return data; }

    //! @name Accessor functions (warning: no bounds checking).
    //@{

    inline
    double& operator() (int row, int col){
      return data[row][col];
    }

    inline
    const double& operator() (int row, int col) const {
      return data[row][col];
    }

    //@}

  protected:

    //! Dimension of square matrix.
    int dim;
    
    //! Data storage, compatible with Epetra_CrsMatrix fill functions.
    double** data;
  };
}

#endif // PERIDIGM_SCRATCHMATRIX_HPP
